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<th colspan="3" align="center">DbEnv::repmgr_set_ack_policy()</th>
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<h2 class="title" style="clear: both"><a id="repmgrset_ack_policy"></a>DbEnv::repmgr_set_ack_policy()</h2>
</div>
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</div>
<pre class="programlisting">#include <db_cxx.h>
int
DbEnv::repmgr_set_ack_policy(int ack_policy); </pre>
<p>
The <code class="methodname">DbEnv::repmgr_set_ack_policy()</code> method specifies how master and
client sites will handle acknowledgment of replication messages which are necessary for
"permanent" records. The current implementation requires all sites in a replication group
configure the same acknowledgement policy.
</p>
<p>
The database environment's replication subsystem may also be configured using the
environment's <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file. The
syntax of the entry in that file is a single line with the string "repmgr_set_ack_policy",
one or more whitespace characters, and the <span class="bold"><strong>ack_policy</strong></span>
parameter specified as a string. For example, "repmgr_set_ack_policy DB_REPMGR_ACKS_ALL".
Because the <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file is read
when the database environment is opened, it will silently overrule configuration done
before that time.
</p>
<p>
Waiting for client acknowledgements is always limited by the
<a class="link" href="repset_timeout.html#set_timeout_DB_REP_ACK_TIMEOUT">DB_REP_ACK_TIMEOUT</a>
specified by the <a class="xref" href="repset_timeout.html" title="DbEnv::rep_set_timeout()">DbEnv::rep_set_timeout()</a> method.
If an insufficient number of client acknowledgements have been
received, then the master will invoke the event callback function,
if set, with the
<a class="link" href="envevent_notify.html#event_notify_DB_EVENT_REP_PERM_FAILED">DB_EVENT_REP_PERM_FAILED</a>
value.
(See the
<a href="../../programmer_reference/rep_mgr_ack.html" class="olink">
Choosing a Replication Manager Ack Policy
</a>section in the
<em class="citetitle">Berkeley DB Programmer's Reference Guide</em> for more information.)
</p>
<p>
The <code class="methodname">DbEnv::repmgr_set_ack_policy()</code> method configures a database
environment, not only operations performed using the specified
<a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> handle.
</p>
<p>
The <code class="methodname">DbEnv::repmgr_set_ack_policy()</code> method may be called at any time
during the life of the application.
</p>
<p>
The <code class="methodname">DbEnv::repmgr_set_ack_policy()</code> <span>
<span>
method either returns a non-zero error value or throws an
exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
</span>
</span>
</p>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp9865528"></a>Parameters</h3>
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp9856984"></a>ack_policy</h4>
</div>
</div>
</div>
<p>
Some acknowledgement policies use the concept of an
electable peer, which is a client capable of being
subsequently elected master of the replication
group. The <span class="bold"><strong>ack_policy</strong></span> parameter
must be set to one of the following values:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p><a id="ackspolicy_DB_REPMGR_ACKS_ALL"></a>
<span class="bold"><strong>DB_REPMGR_ACKS_ALL</strong></span>
</p>
<p>
The master should wait until all replication clients have acknowledged
each permanent replication message.
</p>
</li>
<li>
<p><a id="ackspolicy_DB_REPMGR_ACKS_ALL_AVAILABLE"></a>
<span class="bold"><strong>DB_REPMGR_ACKS_ALL_AVAILABLE</strong></span>
</p>
<p>
The master should wait until all currently connected replication clients have acknowledged
each permanent replication message.
This policy will then invoke the
<a class="link" href="envevent_notify.html#event_notify_DB_EVENT_REP_PERM_FAILED">DB_EVENT_REP_PERM_FAILED</a> event if fewer than
a quorum of clients acknowledged
during that time.
</p>
</li>
<li>
<p><a id="ackspolicy_DB_REPMGR_ACKS_ALL_PEERS"></a>
<span class="bold"><strong>DB_REPMGR_ACKS_ALL_PEERS</strong></span>
</p>
<p>
The master should wait until all electable peers have acknowledged
each permanent replication message.
</p>
</li>
<li>
<p><a id="ackspolicy_DB_REPMGR_ACKS_NONE"></a>
<span class="bold"><strong>DB_REPMGR_ACKS_NONE</strong></span>
</p>
<p>
The master should not wait for any client replication message
acknowledgments.
</p>
</li>
<li>
<p><a id="ackspolicy_DB_REPMGR_ACKS_ONE"></a>
<span class="bold"><strong>DB_REPMGR_ACKS_ONE</strong></span>
</p>
<p>
The master should wait until at least one client site has acknowledged
each permanent replication message.
</p>
</li>
<li>
<p><a id="ackspolicy_DB_REPMGR_ACKS_ONE_PEER"></a>
<span class="bold"><strong>DB_REPMGR_ACKS_ONE_PEER</strong></span>
</p>
<p>
The master should wait until at least one electable peer has
acknowledged each permanent replication message.
</p>
</li>
<li>
<p><a id="ackspolicy_DB_REPMGR_ACKS_QUORUM"></a>
<span class="bold"><strong>DB_REPMGR_ACKS_QUORUM</strong></span>
</p>
<p>
The master should wait until it has received acknowledgements from the
minimum number of electable peers sufficient to ensure that the effect
of the permanent record remains durable if an election is held. This is the default acknowledgement
policy.
</p>
</li>
</ul>
</div>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp9911184"></a>Errors</h3>
</div>
</div>
</div>
<p>
The <code class="methodname">DbEnv::repmgr_set_ack_policy()</code>
<span>
<span>
method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a>
exception, encapsulating one of the following non-zero errors, or return one
of the following non-zero errors:
</span>
</span>
</p>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp9919560"></a>EINVAL</h4>
</div>
</div>
</div>
<p>
If this method is called from a base replication API
application; or if an invalid flag value or parameter was
specified.
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp9917464"></a>Class</h3>
</div>
</div>
</div>
<p>
<a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a>
</p>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp9920952"></a>See Also</h3>
</div>
</div>
</div>
<p>
<a class="xref" href="rep.html#replist" title="Replication and Related Methods">Replication and Related Methods</a>
</p>
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